Volkswagen diesel engines made since 1991 use Turbocharged Direct Injection, or TDI. The 1.9-litre version of this engine appears in various Volkswagen models made since 1995, including the Golf, Jetta, Passat and New Beetle. TDI engines have a turbocharger and inject fuel directly into the cylinder. This is a mechanical method of fuel injection, which does not use an electronic controller to determine when the injector sends fuel to the cylinder.
Remove the fuel pump fuse from the fuse box under the dashboard. Start the engine, and allow it to idle until it stalls. This will relieve the pressure in the fuel system. Turn the engine off, and replace the fuel pump fuse in the fuse box.
Disconnect the negative battery cable with a socket wrench. Wrap a clean shop cloth around the fitting on the fuel line to the fuel rail. Remove the union nuts from the fuel line, and disconnect the fuel line from the fuel rail.
Remove the mounting bolts for the fuel rail with a socket wrench, and disconnect the fuel rail from the engine as an assembly. Turn the fuel injectors counterclockwise and remove them from the injector hole on the cylinder head. Remove and discard the heat shields from the injector hole.
Install new heat shields to the injector hole, and screw the new fuel injector into its hole. Tighten the fuel injector with a socket wrench, and install the fuel rail to the engine.
Connect the fuel line fuel rail, and fasten the union nuts for the fuel line with a socket wrench. Connect the negative battery cable.